Layer utilities

Overview

This module provides a comprehensive set of helper functions for layer classification, caching, editing, saving, and managing layer styles and filters. It also exposes functions for generating layer legends and definitions from imported GeoJSON data.

Classification Functions

isInMemoryLayer(layer)

Returns true if the layer has no _id property (i.e. it exists only in memory and has not been persisted to the catalog).

---

isUserLayer(layer)

Returns true if layer.scope === 'user'.

---

isFeatureLayer(layer)

Returns true if layer.service === 'features'.

---

hasFeatureSchema(layer)

Returns true if the layer has a schema property.

---

isLayerSelectable(layer)

Returns layer.isSelectable (defaults to true).

---

isLayerHighlightable(layer)

Returns layer.isHighlightable (defaults to true).

---

isLayerProbable(layer)

Returns layer.isProbable (defaults to false).

---

isLayerStorable(layer)

Returns true if the layer can be saved to the catalog. Only in-memory layers (no _id) are storable. Defaults to isUserLayer(layer) unless overridden by layer.isStorable.

---

isLayerEditable(layer)

Returns layer.isEditable (defaults to isUserLayer(layer)).

---

isLayerCachable(layer)

Returns true if the layer can be cached for offline use. Defaults to true for base layers, service-backed layers, pmtiles layers, and geoJson layers.

---

isLayerRemovable(layer)

Returns layer.isRemovable (defaults to isUserLayer(layer)).

---

isLayerStyleEditable(layer)

Returns layer.isStyleEditable (defaults to isUserLayer(layer)).

---

isLayerDataEditable(layer)

Returns layer.isDataEditable (defaults to isUserLayer(layer) && isFeatureLayer(layer)).

---

isLayerFilterEditable(layer)

Returns layer.isFilterEditable (defaults to isUserLayer(layer) && isFeatureLayer(layer)).

---

isTerrainLayer(layer)

Returns true if the layer is a terrain layer (type === 'TerrainLayer' or Cesium type Cesium/Ellipsoid).

---

isMeasureLayer(layer)

Returns true if the layer has both variables and service properties.

Cache Functions

isLayerCached(layer)

Checks whether the layer source URL is present in LocalCache.

• Returns: Promise<boolean>

---

setLayerCached(layer, options)

Caches the layer data for offline use. Dispatches to the appropriate cache strategy based on layer type:

• Base layers: Tiles for each zoom level in the given bounds.

• Service layers: Creates an offline features service.

• GeoJSON layers: Caches the source URL response.

• PMTiles layers: Caches tile data including header and directory ranges.

• Parameters:

  • layer (Object): The layer to cache.
  • options.bounds (Array): [[south, west], [north, east]] bounding box.
  • options.minZoom (number, optional): Minimum zoom level. Defaults to 3.
  • options.maxZoom (number, optional): Maximum zoom level.
  • options.nbConcurrentRequests (number, optional): Maximum concurrent cache requests. Defaults to 10.

• Returns: Promise<void>

---

setLayerUncached(layer, options)

Removes cached data for the layer. Mirrors setLayerCached for the corresponding layer type.

• Returns: Promise<void>

---

setBaseLayerCached(layer, options) / setGeojsonLayerCached(layer) / setPMTilesLayerCached(layer, options)

Type-specific cache functions. Prefer the generic setLayerCached.

Edit Functions

editLayerStyle(layer, style, ignoreFeatureStyle?)

Updates the style of a layer. For persisted layers (layer._id), patches the catalog service. For in-memory layers, updates the layer object directly. Regenerates legend and filter style templates as needed.

• Parameters:
  • layer (Object): The layer to update.
  • style (Object): A { point, line, polygon } style object.
  • ignoreFeatureStyle (boolean, optional): When true, sets ignoreFeatureStyle on the patch.
• Returns: Promise<Object> — The updated layer.

---

updateLayerWithFiltersStyle(layer)

Regenerates the style templates for a persisted layer from its filter definitions and patches the catalog service.

• Returns: Promise<void>

---

editFilterStyle(layer, filter, engineStyle, style, ignoreFeatureStyle?)

Updates the style of a specific filter on a layer and regenerates all style templates. Patches the catalog service with the new templates and filter list.

• Returns: Promise<void>

---

getLegendForLayer(layer)

Generates the legend descriptor for a layer without mutating it:

• If the layer has filters with styles, generates a symbol-based legend from filter styles.

• Otherwise generates a single legend from the default layer style.

• Returns: Promise<Object> — A legend patch object { legend, filters? } or { $unset: { legend: '' } } when no filter has a style.

---

getFilterFunctionFromLayerFilters(layer)

Builds a sift-based filter function from the layer's filter definitions. Active filters are combined with filterOperators.active (default $or) and inactive filters with filterOperators.inactive (default $and).

• Returns: Function — A predicate function (item) => boolean.

Layer CRUD Functions

generateLayerDefinition(layerSpec, geoJson)

Populates a layer specification object from a GeoJSON dataset. Sets default engine options (geoJson, realtime), generates a property schema if absent, assigns feature IDs, and extracts custom pane definitions from feature styles.

• Parameters:
  • layerSpec (Object): The layer specification to populate in place.
  • geoJson (Object): A GeoJSON Feature or FeatureCollection.
• Returns: true if the GeoJSON is valid, or undefined on error.

---

saveGeoJsonLayer(layer, geoJson, chunkSize?)

Saves an in-memory GeoJSON layer to the catalog and features service. Validates geometry, uploads features in chunks (default 5000 points per chunk), and enables tiling for large datasets (>5000 points).

• Returns: Promise<Object | undefined> — The created catalog layer, or undefined if the user cancelled after geometry errors.

---

saveLayer(layer)

Saves a layer definition to the catalog service without uploading features.

• Returns: Promise<Object> — The created catalog layer.

---

removeLayer(layer)

Prompts the user for confirmation, then removes the layer from the catalog and (for feature layers) removes all associated features.

• Returns: Promise<boolean> — true if removed, false if the user cancelled.